Help! Manga Name?

I starting reading this manga, but didn't finish because it was still being scanalated at the time. That was a couple years ago, but now I can't remember what it was called.

The first chapter involved a tomboyish girl, whose parents have a shop on the beach. She has a childhood friend whom, if I remember correctly, has a little crush on her. (There is also a big rock on the beach that she and her friend would reminisce about).

On one particular day she is walking on the beach and finds the body of a man. He is dressed from the past and, I think, has a sword. He all of a sudden wakes up and kisses her.

I also remember a special box or something pertaining to the man that is also on the beach...I think. I'm trying to remember, but its been forever since I've read this.

Is any of this coming to mind for anyone?

Thanks so much for your help!!!

________________Life is pleasant, death is peaceful, it's the transition that's troublesome...-Isaac Asminov